This robot destacks blanks and feed them to a bending machine. During  destacking the robot moves the sheet between two dual- head sensors. If the robot vacum cup gripper has picked up 2 sheet instaed of only one, a contact in the double sheet detector amplifier switches. This contact controlls the robot to repeat the destacking process again and again, till the double sheets are removed / shaked off  from each other or, if this is without sucsess, places the double sheets in a separtat double sheet  bin/ stack.